FYI, Weber Copper rectifier & cold solder joints

I just wanted to pass on an interesting find with a problem I had with my ST-70 or so I thought. Recently my ST-70 developed a nasty hum/buzz, after it was warmed up. I built my ST-70 so naturally I thought I must have done something wrong. Today I decided it was time to dig in and see if I could find anything obvious. I started by removing all the tubes then as I tried to remove the Weber copper rectifier the copper cover came off the base, so I held the rec by the base and removed it from the amp. I decided to pull the cover off to see what was inside and noticed one of the leads coming from one of the power resistors was not connected to the PCB inside next to the base. At first I thought I may have broken off the lead, upon closer inspection it was actually a cold solder joint and the lead came clean out of its soldered joint and was NOT broken off. The other resistors lead did not look so good so I soldered both of the leads, put everything back together and all is well.

Just thought I would pass this little tid-bit of info on as I would have chased my tail forever had the cover stayed attached to the base.

I have found the Weber Copper Caps to be very reliable - yet - every now and then one unit with dubious solder joints can get by their inspection process. As to the copper tube coming off the base. Weber uses an adhesive to keep these together. The adhesive does not adhere as well when the copper cap is hot or even warm. You should wait until the cap is dead cold before removing the cap from the rectifier tube socket.